[ RadSafe ] Thorium! Thorium reactor remixed lecture in 16 minutes

[Jim Darrough]

Thanks for that wonderful explanation George.

Regards, Jim

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of George Stanford
Sent: Thursday, February 03, 2011 2:26 PM
To: Michael McNaughton
Cc: radsafe at health.phys.iit.edu
Subject: Re: [ RadSafe ] Thorium! Thorium reactor remixed lecture in 16
minutes

Michael:

      The short answer is that it's pretty much equivalent, if not a little
worse.  The thorium reactor is no more exempt from the need for safeguards
than any other type of reactor.

      Details:

(A)   First of all, any uninspected reactor can be modified to 
irradiate special U-238 fuel elements for short periods of time, to yield
high-quality Pu-239 for weapons.  But with a thorium reactor, the
modifications might have to be much more extensive than with a uranium
reactor.

(B)  However, be aware that, regardless of how many reactors a nation has,
it will not me able to make any A-bombs without one of
these:  (a) an enrichment capability (for U-235 bombs), (b) a PUREX-type of
fuel reprocessing facility (for Pu-239 bombs) or (c) a facility for
extracting Pa-233 from thorium fuel (for U-233 bombs).  Hence the need for
inspectors, and for international supervision of enrichment and
fuel-processing facilities.

(C)  Some thorium enthusiasts (not all) like to point out (correctly) that
the U-233 in a thorium reactor is hopelessly contaminated with U-232.  But
what they sometimes don't mention (and didn't in that rapid-fire YouTube
video) is that at least some of the proposed thorium cycles involve running
the liquid fuel through a processor that chemically separates Pa-233 from
the mix before it decays to become pure U-233 (which is a superior bomb
material) -- easily diverted for bombs.  But see (D), next.

(D)  The standard thorium-supporter's response to that Pa situation seems to
be that the breeding potential of thorium reactors is so poor that diverting
Pa would shut the reactor do\wn for lack of fissile material.  However, the
initial charge of a thorium reactor has to be spiked with enough fissile in
(low-quality) Pu-239 or low-enriched uranium to permit it to become critical
in the first place.  Thus the infrastructure would be in place for
substituting crappy uranium of plutonium for the Pa-233 diverted from the
operating reactor.

(E)  The bottom line is that an unsafeguarded thorium reactor could rather
readily serve as an efficient mechanism for converting weapons-useless
uranium or plutonium into highly usable U-233.  Inspectors would be needed.

      Does this help?

      --  George Stanford
      Reactor physicist,retired

~~~~~~~~~~~~~~~~~~~~~~~~~~

----- Original Message -----
From: "Michael McNaughton" <mcnaught at lanl.gov>
To: "The International Radiation Protection (Health Physics) Mailing List"
<radsafe at health.phys.iit.edu>
Sent: Thursday, February 3, 2011 2:40:11 PM
Subject: Re: [ RadSafe ] Thorium! Thorium reactor remixed lecture 
in        16        minutes

Is the "proliferation" problem with a thorium reactor better or worse than
with a conventional reactor?


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu 
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jim Darrough
Sent: Thursday, February 03, 2011 1:06 PM
To: 'The International Radiation Protection (Health Physics) Mailing List'
Subject: Re: [ RadSafe ] Thorium! Thorium reactor remixed lecture in 16
minutes

If you talk to a Nuclear Engineer, and mention Th or U-233, the deal is
dead. They start parroting "proliferation" and become focused on the
possible production of weapons.

I think the Thorium fuel cycle is well worth the investment, but the
political rhetoric that has clouded the thinking of the people who can make
the decision to utilize it must be overcome. That is the real issue here.

Jim Darrough

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and 
understood the RadSafe rules. These can be found at: 
http://health.phys.iit.edu/radsaferules.html

For information on how to subscribe or unsubscribe and other settings 
visit: http://health.phys.iit.edu

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the
RadSafe rules. These can be found at:
http://health.phys.iit.edu/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit:
http://health.phys.iit.edu